Measurements of Centimetre-scale Temperature Gradients at the Ice-water Boundary of Floating Glacier Ice
Abstract
Understanding the response of land-based ice to changes in ocean forcing is critical to making reliable projections of sea level rise on multi-decadal and century timescales. Subglacial discharge plumes have generally been assumed to be the dominant driver of submarine melting, but direct measurements of submarine melt rates, both within and outside of discharge plumes, are difficult to acquire and remain sparse as a result. Observations and modelling of submarine melting at tidewater glaciers and ice shelves largely rely on parameterizations in which subglacial discharge controls the overall submarine melt. However, several recent studies have suggested that ambient melting rates, outside of discharge plumes, at tidewater glaciers are higher than would be expected based on the existing theory. Direct measurements of processes such as mixing and heat transport at the ice-ocean boundary itself, on scales on the order of centimetres, will be essential to understanding current rates of submarine melting, and predicting future submarine melt.
We present results from a field campaign conducted in July 2022 in Hornsund Fjord, Svalbard. Measurements of water temperature were collected immediately adjacent to the submerged face of floating pieces of ice with diameters of about 3-10m. The spatial resolution of our measurements is less than 1 cm. We find temperatures of 1-2°C within a few centimetres of the ice face, and thermal gradients on the order of 0.5°C/cm. Possible implications of these observations in the context of theoretical descriptions of the ice-water boundary layer will be discussed, along with future steps for more thorough observational characterization of processes occurring at the ice-water boundary layer.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.C15D0616J